For welding, either AC or DC, with a gated bridge, such as an SCR bridge as shown in Samodell U.S. Pat. No. 6,388,232, it is difficult to weld at very low currents, i.e. of less than about 8.0 amperes. At low currents, the individual SCR switches of the gated bridge are phased back to produce a series low current pulses, which pulses are smoothed out by a DC choke. However, at low amperes, the arc is unstable and tends to be extinguished. To solve this dilemma, The Lincoln Electric Company of Cleveland, Ohio developed its Microstart welder, shown generally in Samodell U.S. Pat. No. 6,388,232. This patented power source incorporates a supplemental power supply which is initiated during low current welding. Lincoln's electric arc welder has experienced substantial commercial success; however, due to the additional components and accessories, the welder is somewhat expensive. In some instances, the added expense of the welder is not justified by the particular welding application. Thus, customers often purchased electric arc welders not having the unique low current abilities of the Microstart welder. In the prior units, at open circuit voltage(OCV) the supplemental power supply would have current flow causing high power dissipation. Consequently, there is a commercial need for a low cost electric arc welder of the type using a gated bridge type power source which can operate at low currents, i.e. less than about 8.0 amperes and, indeed, less than 3.0 amperes. Also, the power source should be such there is minimal power dissipation during open circuit voltage when there is no power directed to the arc. As disclosed in Schwartz U.S. Pat. No. 6,384,373 prior units employing separate, supplemental power supplies require a filter including a capacitor or inductor. It is desirable to avoid the high cost of these filter components. These prior arc welders used large output chokes so low level operation caused the arc performance to be erratic and difficult to control. Low current welding used a separate or supplemental power supply superimposed on the output circuit of the main welder power source. In this manner, background current was used to replace the main current. The background current did not merely augment the SCR current. This operation was difficult to control. All of these disadvantages of prior gated bridge type power sources for use in AC and DC electric arc welders are overcome by the present invention.